Industrial mills are used to process mined ores and cement, breaking these materials apart into smaller constituents for further processing or transportation. Mills generally include a housing with a feeder inlet for receiving the raw materials. A grinding media, such as ceramic balls, may be enclosed within the housing. The grinding media generally has a hardness greater than the raw materials so that continuous collisions with the grinding media cause the raw material to break apart. In some instances, the raw materials may be ground in a mill without the addition of a grinding media, but by colliding with itself.
Some mills, such as vertical tower mills (e.g., that use a screw-shaft) and horizontal axis mills (e.g., autogenous grinding mills, semi-autogenous grinding (SAG) mills, rod mills, and ball mills) have a lifting member to elevate the raw material or combined mixture of grinding media and raw material. The combined mixture then falls from the lifting member back to a bottom area of the mill, providing collisions between the grinding media and the raw material, as well as with the bottom surface of the mill. The lifting member may continuously rotate through the combined mixture causing a continuous cascade and/or stirring of the material, effectively breaking it apart.
However, the raw material or combined mixture of grinding media and raw material can cause some portions of the internal components of the mill to experience greater wear than other portions. Even when a relatively small portion of a component wears down, the entire component must be replaced, which can increase the costs of maintaining the mill. Furthermore, milling activity must be halted to replace the worn component, negatively impacting productivity. Some milling components can weigh between 500 and 2,000 lbs, so installing/replacing them requires substantial man power and safety concerns.